TW201724165A - Plasma etching photoresist device - Google Patents

Abstract

The invention discloses a plasma etching photoresist device comprising a reaction chamber and a reaction gas source disposed above the reaction chamber. a susceptor is disposed in the reaction chamber for supporting the substrate, and at least one gas distribution plate is disposed above the substrate for uniformly distributing the reaction gas to the surface of the substrate, wherein the gas distribution plate comprises an aluminum or aluminum alloy body and is covered by the substrate The protective layer outside the body. By providing a protective layer with a suitable thickness outside the aluminum or aluminum alloy body, the gas distribution plate disposed in the reaction chamber of the present invention can effectively adsorb the charged particles in the plasma and avoid the oxygen distribution of the gas distribution plate. The consumption of free radicals can reduce the accumulation of charged particles on the substrate surface and reduce the current on the substrate surface while maintaining a high oxygen radical concentration in the reaction chamber. Thereby, the etching rate of the substrate photoresist is maintained at a high level.

Description

Plasma etching photoresist device

The present invention relates to a plasma etch photoresist device and the design of its internal components.

In the semiconductor wafer manufacturing process, the photoresist is used to transfer the pattern on the mask to the wafer to achieve the purpose of etching the substrate according to the design on the mask. After the substrate etching process is finished, the photoresist is usually required to be removed. The wafer surface is stripped for the next process.

In the prior art, a plasma processing apparatus for removing photoresist generally includes a reaction chamber, and a reaction gas source disposed above the reaction chamber. The reaction gas in the reaction gas source mainly includes oxygen, and the oxygen is dissociated into electricity. The slurry can effectively remove the photoresist on the surface of the substrate by using oxygen radicals in the plasma. In order to ensure that the oxygen dissociated plasma and the undissociated reaction gas can uniformly reach the surface of the substrate, the substrate is uniformly etched, and the reaction chamber further includes at least one gas distribution plate, and the gas distribution plate is provided with a gas diffusion hole to realize the reaction. Uniform distribution of gas. In addition to the requirement of uniform distribution of the plasma involved in the reaction, the photoresist removal operation of the substrate also requires plasma concentration. The higher the concentration of oxygen radicals participating in the reaction, the faster the etching rate of the substrate.

In the prior art, the material of the gas distribution plate is an important factor affecting the distribution and concentration of the plasma. If the gas distribution plate cannot adsorb the charged particles in the plasma, the charged particles will accumulate on the surface of the substrate, so that there is a surface on the substrate. The large current reduces the etching rate; if the gas distribution plate can adsorb both charged particles and neutral radicals, the concentration of the raw materials participating in the etching reaction in the reaction chamber is lowered, resulting in a decrease in the photoresist etching operation rate of the substrate.

The present invention provides a plasma etching photoresist device comprising a reaction chamber and a plasma dissociation channel disposed above the reaction chamber, wherein a susceptor is disposed in the reaction chamber for supporting the substrate, and at least one gas is disposed above the substrate The distribution plate is used to uniformly distribute the reaction gas to the surface of the substrate, and the gas distribution plate includes an aluminum or aluminum alloy body and a protective layer coated on the outside of the body.

Preferably, the protective layer material is an engineering plastic that can be coated.

Preferably, the protective layer is one of Teflon, ceramic, POM, PEEK, ULTEM.

Preferably, the protective layer material is free of metallic elements.

Preferably, the protective layer is disposed on the outer surface of the aluminum or aluminum alloy body by electroplating, spraying, evaporation or soaking.

Preferably, the protective layer has a thickness of less than 0.1 mm.

Preferably, the reaction chamber includes a first gas distribution plate adjacent to the plasma dissociation channel and a second gas distribution plate adjacent to the substrate, between the first gas distribution plate and the second gas distribution plate A certain distance is set, the first gas distribution plate performs a first gas distribution on the reaction gas, and the second gas distribution plate performs a secondary gas distribution on the reaction gas.

Preferably, the first gas distribution plate and the second gas distribution plate are provided with a plurality of gas diffusion holes, and the gas diffusion holes on the second gas distribution plate are uniformly distributed.

Preferably, the projections of the gas diffusion holes on the first gas distribution plate and the second gas distribution plate on the substrate surface do not overlap.

Preferably, the reaction chamber comprises a sidewall of the cavity and an upper cover disposed on the sidewall of the cavity, and the upper cover is provided with an opening for allowing plasma and reactive gas in the plasma dissociation channel to pass under the upper cover A guide tube whose inner diameter gradually increases from the opening is provided to guide the plasma and the reaction gas to the gas diffusion plate.

The invention has the advantages that: by providing a protective layer with a suitable thickness outside the aluminum or aluminum alloy body, the gas distribution plate disposed in the reaction chamber of the invention can effectively adsorb the charged particles in the plasma, and can Avoiding the reaction of oxygen radicals in the reaction chamber with aluminum or aluminum alloy, reducing the consumption of oxygen radicals by the gas distribution plate, thereby maintaining the concentration of high oxygen radicals in the reaction chamber while reducing the charged particles on the surface of the substrate. Accumulation, reducing the current on the surface of the substrate. Thereby, the etching rate of the substrate photoresist is maintained at a high level.

In order to describe the present invention in detail, the instant mode of the present invention is described below in conjunction with the drawings.

1 is a plasma etching photoresist device according to the present invention, the device includes a cavity 1 enclosing a reaction chamber, and an upper portion of the cavity 1 is provided with a flow guiding tube 3 for guiding gas flow, and the cavity 1 The lower part is provided with a sealing plate 4, and an exhaust port and an exhaust device (not shown) connected to the exhaust port are provided on the sealing plate for discharging reaction by-products out of the reaction chamber and adjusting the air pressure in the reaction chamber. An upper cover 2 is disposed on the upper portion of the draft tube 3, and the wafer 9 is disposed on the base 5 inside the cavity 1. The restrictor ring 6 is disposed at the periphery of the base, sealingly connected with the guide tube 3, and a reaction gas is disposed outside the reaction chamber. Source 10, the gas in the source of reactive gas enters the plasma dissociation channel 11 and is dissociated into plasma. The upper cover 2 and the draft tube 3 are provided with an opening connected to the plasma dissociation channel 11, and the plasma in the plasma dissociation channel 11 and the undissociated reaction gas enter the reaction chamber to participate in the etching operation of the photoresist. Since the reaction gas is not 100% ionized in the plasma dissociation channel 11, the gas flow mentioned in the following description of the present invention actually comprises a mixture of an ionized reaction gas and an ionized plasma, the plasma containing neutral radicals, Sexual free radicals are the main reactants for etching photoresist.

The reaction gas in the reaction gas source mainly includes oxygen. By dissociating the oxygen into a plasma, the photoresist at the surface of the substrate can be effectively etched by using oxygen radicals in the plasma. In the present invention, the reaction chamber further includes at least one gas distribution plate 7, and the gas distribution plate is provided with a gas diffusion hole to achieve uniform distribution of the reaction gas, and to ensure uniformity of the oxygen dissociated plasma and the undissociated reaction gas. The substrate is reached and the substrate is uniformly etched.

The photoresist etching operation is expected to maintain a high etching rate, and the etching uniformity of each region on the substrate is ensured. That is to say, in the photoresist etching operation of the substrate, in addition to the requirement of uniform distribution of the plasma participating in the reaction, there is also a requirement for the concentration of the plasma. The higher the concentration of oxygen radicals participating in the reaction chamber, the faster the etching rate of the substrate.

The gas distribution plate 7 can evenly distribute the plasma, and the difference in material can also affect the concentration distribution of the plasma in the reaction chamber. When the gas distribution plate 7 is made of an insulating material such as quartz, since the insulating material cannot adsorb the charged particles in the plasma, the charged particles pass through the gas diffusion holes of the gas distribution plate to reach the surface of the substrate, and accumulate on the surface of the substrate, so that the surface of the substrate exists. Large current, easy damage to the substrate, affecting the life of the substrate. If the gas distribution plate is made of a metal material, the gas distribution plate not only adsorbs the charged particles but also consumes the neutral radicals involved in the etching reaction, resulting in a decrease in the concentration of the raw materials participating in the etching reaction in the reaction chamber, so that the photoresist etching operation rate of the substrate is lowered. .

In order to improve the above problem and ensure the photoresist etching rate of the substrate, the present invention selects the gas distribution plate shown in FIG. 2, and the gas distribution plate selects the main body 71 of aluminum or aluminum alloy, in the reaction chamber of the present invention, The outer wall and several components in the reaction chamber are made of aluminum or aluminum alloy. Therefore, the invention selects aluminum or aluminum alloy material as the main material of the gas distribution plate to effectively avoid introduction of pollution. Since aluminum or aluminum alloy easily forms an aluminum oxide film on the surface in air, if a gas distribution plate with an aluminum oxide film is directly placed in the reaction chamber of the plasma etching photoresist device, oxygen radicals in the reaction chamber will be Displacement reaction with oxygen in the aluminum oxide film produces a substance that cannot participate in substrate etching, thereby reducing the photoresist etching rate. The present invention is provided by coating a protective layer 72 on the outside of the main body 71. The material of the main body 71 is separated from the oxygen radicals to avoid the reaction between the two, so that the concentration of oxygen radicals in the reaction chamber can be effectively maintained. The protective layer 72 is preferably a material resistant to plasma corrosion. In this embodiment, a Teflon material is selected. In other embodiments, other engineering plastics such as POM (polyoxymethylene resin), PEEK (polyether ether ketone), ULTEM ( Polyether quinone imine) and the like. The protective layer 72 may be applied to the outer surface of the aluminum or aluminum alloy body by plating, spraying, evaporation, and immersion. The invention selects the manner of spraying, and in other embodiments, the plating method may also be selected, and the aluminum or aluminum alloy body 71 provided with the gas diffusion hole is placed in the plating solution to spread on the outer surface of the aluminum or aluminum alloy body 71 and the gas. A protective layer 72 is formed in the holes. The thickness of the protective layer 72 is not too thick, and the thickness of the protective layer 72 is too large, which causes the gas distribution plate to weaken the adsorption capacity of the charged particles in the plasma, causing the current on the surface of the substrate to become larger, and reducing the etching rate of the photoresist on the surface of the substrate. Preferably, the thickness of the protective layer 72 of the present invention is less than 0.1 mm.

Since a protective layer with a proper thickness is disposed outside the main body of the aluminum or aluminum alloy, the gas distribution plate disposed in the reaction chamber of the present invention can effectively adsorb the charged particles in the plasma and avoid the oxygen freeness of the gas distribution plate. The consumption of the base can reduce the accumulation of charged particles on the surface of the substrate while maintaining the high oxygen radical concentration in the reaction chamber, and reduce the current on the surface of the substrate. Thereby, the etching rate of the substrate photoresist is maintained at a high level.

In order to better achieve the diffusion of the reaction gas, FIG. 3 shows a plasma processing apparatus provided with a dual gas distribution plate. In the embodiment shown in FIG. 3, the reaction chamber includes the reaction gas. The first gas distribution plate 7a of the source and the second gas distribution plate 7b adjacent to the substrate are disposed with a certain distance between the first gas distribution plate 7a and the second gas distribution plate 7b. The first gas distribution plate 7a is for performing a primary gas distribution on the reaction gas, and the second gas distribution plate 7b is for performing a secondary gas distribution to the reaction gas. A more uniform gas distribution can be obtained by the two-stage gas distribution by the first gas distribution plate 7a and the second gas distribution plate 7b. A plurality of gas diffusion holes are disposed on the first gas distribution plate and the second gas distribution plate, and the gas diffusion holes on the second gas distribution plate are evenly distributed.

In addition to improving the uniformity of plasma distribution on the surface of the substrate, the dual gas distribution plate can also protect the photoresist on the surface of the substrate. The reason is that the gas in the reaction gas source emits strong ultraviolet rays during the dissociation into the plasma in the plasma dissociation channel 11, and if the ultraviolet light directly hits the surface of the substrate, the photoresist is damaged, so that the surface of the substrate is light. The etching resistance is uneven. In the present embodiment, the projections on the surface of the substrate are not overlapped by providing the gas diffusion holes on the first gas distribution plate 7a and the second gas distribution plate 7b. The ultraviolet light is not irradiated onto the photoresist on the surface of the substrate to protect the substrate.

Figure 4 specifically illustrates the flow direction and distribution of the reactant gases in the chamber 1. As indicated by the arrows, the gas in the source of reactive gas 10 is ionized into a plasma in the plasma dissociation channel 11, and the plasma and the non-ionized gas enter the treatment zone 20 under the guidance of the draft tube 3 and reach the gas distribution plate. Above, the airflow passes through the through hole in the gas distribution plate 7, reaches the surface of the wafer, passes through the restrictor ring from the periphery of the pedestal, and finally exits the outside of the cavity by the exhaust device, and the charged particles in the gas flow flow through the gas distribution plate. It is adsorbed by the gas step plate, so that the substances reaching the surface of the substrate mainly include unionized gas and neutral radicals in the plasma. The gas distribution plate of the invention can obtain uniform gas distribution in the space, and by providing a protective layer outside the aluminum or aluminum alloy body, the charged plasma can be prevented from collecting on the surface of the substrate, causing excessive current on the surface of the substrate, and Avoid gas distribution plates to reduce the concentration of oxygen radicals and ensure that the substrate is maintained at a higher etch rate.

The invention avoids the ultraviolet light generated by gas ionization to the surface of the wafer, optimizes the gas flow rate on the surface of the wafer, and obtains a uniform gas distribution, thereby achieving a uniform etching rate on the surface of the wafer.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the description Various modifications and alterations of the present invention will be apparent to those skilled in the art. Therefore, the scope of the invention should be limited by the scope of the appended claims.

1‧‧‧ cavity
2‧‧‧Upper cover
3‧‧‧Drainage tube
4‧‧‧ Sealing plate
5‧‧‧Base
6‧‧‧Limited loop
7‧‧‧ gas distribution board
71‧‧‧ Subject
72‧‧‧Protective layer
7a‧‧‧First gas distribution plate
7b‧‧‧second gas distribution plate
9‧‧‧ wafer
10‧‧‧Responsive gas source
11‧‧‧ Plasma Dissociation Channel
20‧‧‧Processing area

Fig. 1 is a view showing the structure of a plasma processing apparatus according to the present invention.

Fig. 2 is a view showing the structure of a gas distribution plate in the plasma processing apparatus.

Fig. 3 is a view showing the structure of another embodiment.

Fig. 4 is a view showing the flow of gas in the reaction chamber shown in Fig. 1.

1‧‧‧ cavity

2‧‧‧Upper cover

3‧‧‧Drainage tube

4‧‧‧ Sealing plate

5‧‧‧Base

6‧‧‧Limited loop

7a‧‧‧First gas distribution plate

7b‧‧‧second gas distribution plate

9‧‧‧ wafer

10‧‧‧Responsive gas source

11‧‧‧ Plasma Dissociation Channel

Claims (10)

A plasma etching photoresist device includes a reaction chamber and a reaction gas source disposed above the reaction chamber, wherein a susceptor is disposed in the reaction chamber for supporting a substrate, wherein at least one gas distribution plate is disposed above the substrate A gas distribution plate is disposed to uniformly distribute the reaction gas to the surface of the substrate, and the gas distribution plate comprises an aluminum or aluminum alloy body and a protective layer covering the exterior of the body, the protective layer is used to protect the aluminum or aluminum alloy body from The reaction gas in the reaction chamber reacts. The device of claim 1, wherein the protective layer material is an engineering plastic that can be coated. The device of claim 2, wherein the engineering plastic comprises Teflon, POM, PEEK or ULTEM. The device of claim 1, wherein the protective layer material is free of metal elements. The device of claim 2, wherein the protective layer is disposed on the outer surface of the aluminum or aluminum alloy body by electroplating, spraying, evaporation or soaking. The device of claim 1, wherein the protective layer has a thickness of less than 0.1 mm. The apparatus of claim 1, wherein the reaction chamber includes a first gas distribution plate adjacent to the reaction gas source and a second gas distribution plate adjacent to the substrate, the first gas distribution plate and the A distance is set between the second gas distribution plates, the first gas distribution plate performs a first gas distribution on the reaction gas, and the second gas distribution plate performs a secondary gas distribution on the reaction gas. The device of claim 7, wherein the first gas distribution plate and the second gas distribution plate are provided with a plurality of gas diffusion holes, and the gas diffusion holes on the second gas distribution plate are uniformly distributed. The device of claim 8, wherein the projection of the gas diffusion holes on the first gas distribution plate and the second gas distribution plate on the substrate surface does not overlap. The apparatus of claim 1, wherein the reaction chamber comprises a cavity sidewall and an upper cover disposed on the sidewall of the cavity, the upper cover being provided with an opening for allowing plasma to dissociate the plasma in the channel And the reaction gas passes, and a guide tube whose inner diameter gradually increases from the opening is disposed under the upper cover, and the plasma and the reaction gas are guided to the gas diffusion plate.